Compilare: user.cpp: In function ‘void dfs(std::vector<std::vector<int> >&, std::vector<int>&, int)’: user.cpp:25:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a[x].size(); i++) ^ user.cpp: In function ‘void citire(std::vector<std::vector<int> >&)’: user.cpp:16:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:53:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.in", "r", stdin); ^ user.cpp:54:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dfs.out", "w", stdout); ^ user.cpp:56:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^